Numerous traffic control systems are now in use. In the most common type, four or eight signal standards are erected at the four corners of an intersection of two mutually crossing streets. Each of these standards has a number of traffic light signal units mounted on it to indicate on which street drivers of vehicles have the right of way for crossing the other street. More particularly, the light signal unit typically has three lights, a "GO" condition, a caution, or "SLOW" down, condition, and a "STOP" condition respectively. An automatic controller mounted at the intersection, controls these traffic light units. The controller also normally includes means for operating the street lights at the intersection so that they are energized to provide illumination at night and are deenergized to reduce power consumption during the day. Some of such traffic signals operate automatically, constantly cycling through a "GO" condition, a "SLOW", that is a slow down, or caution, condition, or a "STOP" condition sequentially over and over. Other systems are traffic actuated, that is, they respond automatically to the flow of traffic so as to provide longer, and/or more frequent, crossing periods in the direction in which traffic flow is heavy, and shorter, and/or less frequent, crossing periods in the direction in which traffic flow is low.
Traffic signals are also provided sometimes at points between successive intersections, such as in the middle of a block. And these traffic conditions are set in a "GO" condition for traffic flowing on the street, but may be actuated by a switch operated by a pedestrian to bring the flow of traffic to a halt and to permit him to cross safely.
In all such systems, it is common to provide additional signal for indicating to pedestrians whether it is safe for them to cross the street. These signals usually include a "WALK" sign, and a "DONT WALK" sign. In addition, the controller not only actuates the "WALK" and "DONT WALK" signs in synchronism with the operation of the traffic signals, but also provide intermittent power to cause the "DONT WALK" sign to flash intermittently during a period when it is dangerous to start. Such danger arises because the "WALK" interval, being finite, may terminate while a person starting to cross the street does not arrive at the other side before the "GO" signal becomes illuminated to allow traffic to flow on the street that he is crossing. The controller not only operates the traffic signals and the overhead street lighting, but also provides the signals for causing the "WALK" and "DONT WALK" signs to be actuated in synchronism therewith. Thus, the "WALK" sign is energized to permit pedestrians to walk across the street in the direction of flow of traffic during a particular period when it is relatively safe to do so, and a "DONT WALK" sign to warn the pedestrian that it would be very dangerous to cross the street. The intervals of energization of the "WALK" and "DONT WALK" signals are not usually the same as the intervals of energization for the "GO" and "STOP" signals. Nevertheless, they are synchronized therewith for the security of pedestrians and drivers of vehicles.
Such "WALK" and "DONT WALK" signals are commonly in the form of neon tubes. These tubes emit green or white light during the "WALK" period and red light during the "DONT WALK" period. They also may be in the form of printed signs that are illuminated by incandescent lights.
This invention will be described with reference to its improvements and advantages over the present pedestrian traffic control systems of the type that employ tubular gaseous discharge lamps, commonly called neon lights even though there may be no neon sign involved, to indicate the "WALK" and "DONT WALK" conditions, and particularly with reference to such a system in which pushbuttons are provided on the standards for actuating the pedestrian traffic control system.
In the pedestrian actuated traffic control systems, switches are mounted on the signal standards which can be operated by pedestrians to actuate systems. In this way, the pedestrian traffic control system is actuated only when needed.